Swingable Thermal Head Mounting for Uniform Printer Contact
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Solution Overview
Problem
In printers where the openable-closable section is connected to the main body rotationally orthogonal to the width direction of the recording paper, the thermal head unit and platen roller often fail to uniformly contact, leading to uneven print quality due to varying contact pressure along the width of the paper.
Innovation Solution
A printer design featuring a head unit with projections and a head frame that allows the head unit to swing around axes parallel to the rotary shaft and the width direction of the paper, using biasing members to ensure uniform contact with the platen, facilitated by notches and movement restrictors to guide and restrict movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the openable-closable section is connected to the main body to be rotationally movable about a rotary shaft orthogonal to the width direction of the recording paper, then the printer can be compact and have easy access to internal components, but the head unit and platen fail to uniformly contact each other in the width direction
Solution Approach 1:
The head unit is made swingable relative to the platen through the projection-notch mechanism, allowing it to dynamically adjust its position and tilt angle to compensate for the rotational movement of the openable-closable section, thereby maintaining uniform contact pressure across the width direction
Solution Approach 2:
The biasing member applies a biasing force to the head unit, changing the contact pressure parameter to ensure uniform contact with the platen across the width direction, compensating for the geometric distortion caused by the rotational connection
2Device complexity
If the thermal head unit is supported by being hooked only at a substantially central position, then the structure is simple, but the head unit cannot compensate for uneven wear of the platen roller in the width direction
Solution Approach 1:
The head unit is made swingable through the projection-notch mechanism, allowing it to dynamically adjust its tilt angle to compensate for uneven wear of the platen roller, ensuring uniform contact pressure across the width direction
Solution Approach 2:
The biasing member applies a biasing force to the head unit, changing the contact pressure parameter to maintain uniform contact with the platen roller, compensating for wear-induced variations
Data Source
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AI summary
In a printer according to an embodiment of the present disclosure, a head unit (41) includes projections (41p) which project toward the rear in a conveying direction (X-axis direction) of recording paper, and with one projection provided at each location between the center and respective ends of the head unit (41) in a longitudinal direction along a width direction (Y-axis direction) of the recording paper. The head frame (23) includes notches (23c) configured to accommodate projections (41p), a movement restrictor (MR) which contacts a part of the head unit (41) from both sides in the longitudinal direction of the head unit (41), and biasing members (23p) configured to bias the head unit (41) toward the platen. Each of the notches (23c) is provided to form a space between itself and the projection (41p), such that the head unit (41) is allowed to swing around an Ax-axis parallel to a rotary shaft (the X-axis direction) of the openable-closable section and an axis parallel to the width direction of the recording paper.